Sheet handling apparatus



March 25, 1969 YARGER ETAL 3,434,710

SHEET HANDLING APPARATUS Filed Oct. 15, less Shet of 2 INVENTOR. NORMANL. YARGER BY ROBERT H. LIVA A TTORNEVS' A March 1969 N. L. YARGER ETAL3,434,710

SHEET HANDL ING APPARATUS Filed 0c.15, 1966 Sheet 2 of2 I] It I A lg z IQ in] m W 11 t INVENTOR.

NCRMAN L. YARGER BY ROBERT H. LIVA 3,434,710 SHEET HANDLING APPARATUSNorman L. Yarger, Ontario, and Robert H. Liva, Rochester, N.Y.,assignors to Xerox Corporation, Rochester, N.Y., a corporation of NewYork Filed Oct. 13, 1966, Ser. No. 586,474 Int. Cl. B65h /06 U.S. Cl.271--51 11 Claims ABSTRACT OF THE DISCLOSURE Anti-buckling apparatuswithin a sheet transport system for moving flexible sheets. the sheetsare prevented from buckling by inserting in the path of movement of thesheets a member that extends into the path of travel of the sheets andcauses sheets passing the point where the member protrudes into the pathof travel to bow adding beam strength to the sheet thus providing themwith subsantial rigidity.

This invention relates to sheet transport devices and particularly toapparatus for preventing the buckling of flexible sheets.

During the transport of sheet material, there is often a distance overwhich the sheet must travel where it is not supported by any member. Ifthis distance is equal to more than a few inches, there is a tendencyfor the sheet to buckle or turn-under due to the force of gravity andmoment arm created by its own weight. In machine feeding sheets offlexible material, e.-g., paper or plastics, to a final depository, suchas the copy holder tray of an office copier apparatus, this bucklingcauses a difficulty in stacking the final copy sheets. The problembecomes all the more critical if the copy holder tray is an uphill traytilted rearward from the horizontal, being lower at the end nearest theemerging of a copy sheet than at the end adapted to maintain the frontof the copy sheet.

Buckling of the sheets being deposited in the copy tray will causesucceeding sheets to be misaligned and perhaps fed, not into, but overand out of the depository tray as they slide over the previous buckledsheet causing a paper jam.

It is therefore an object of this invention to improve the transport ofsheets over a gap in their path of travel.

Another object of this invention is to prevent the buckling of sheetsunder the force of gravity.

Yet another object of this invention is to impart a rigidity to aflexible sheet for prevention of buckling of the sheet.

A further object is to impart a beam strength to a sheet Whilepreventing its creasing.

Still another object of this invention is to insure that flexible sheetswill not buckle or invert when delivered to a depository tray.

These and other objects of the invention are attained by means of anapparatus for forcing the center of a flexible sheet material below theedges thereof, across its entire cross section, as the sheet is fedthrough its last set of guides and to maintain the sheet in this posiionwith a force thereon readying it for engagement by the next operablemember in its path while maintaining it in a rigid state.

For a better understanding of the invention as well as other objects andfurther features thereof, reference is had to the following detaileddescription of the invention to be read in conjunction with theaccompanying drawings wherein:

FIG. 1 is a side view, partly in section, of a sheet transport mechanismand depository tray;

United States Patent 0 3,434,710 Patented Mar. 25, 1969 FIG. 2 is a sideview of a buckler finger in conjunction with a pair of pinch rollers;

FIG. 3 is a side view of another embodiment of a buckler finger inconjunction with a pair of pinch rollers; and

FIG. 4 is a front view of a sheet transport apparatus embodying thisinvention.

Referring now to the drawing, there is shown in FIG. 1 a sheet transportdevice of the type that would be found within the super structure 8 ofan office copier type machine. It is comprised of guides and pinchrollers the latter being driven by a suitable drive means and belts andgear connections (not shown). The apparatus functions to bring flexiblesheet material from a previous operation to be deposited in the sheetholder 10.

The sheet is carried by sets of pinch rollers 12, 14, 16 and 18, allformed of metal in a cylindrical shape and plates 20, 22, and 24 used toguide the lead edge of the sheet transported therethrough to the nextset of pinch rollers and finally out of the transport mechanism. Therollers are journaled in the frames of the super structure 8 supportingthe transport section and are free to rotate in a direction to carry thesheet from a previous operation to a next operation, such as depositionin the sheet holder 10. The rotation of each set is accomplished bysuitable belts and gears attached to a drive motor (not shown). Only oneroller of each set is driven while the other rotates due to frictionagainst the O-rings, such as O-ring 34, of the driver roller. The guideplates 20 through 24 are formed and spaced to prevent buckling of thesheet as it is pushed by the rollers into contact with the guides. Theguides may be formed by stamping and have attached thereto, either as anintegral part thereof or in some other manner fastened thereon, bracketssuch as those indicated by reference numeral 26. The brackets may befastened to the transport super structure 8 by any means such as screws28.

The last set of pinch rollers in the super structure 8 is comprised of alower drive roller .30 formed in a cylindrical shape and connected witha shaft 32 appropriately attached to drive belts connected to a motorcausing the rotation of said lower drive pinch roller 30 in acounterclockwise motion as viewed from the right-hand side of the superstructure as shown in FIG. 1. The roller 30 has several notches placedtherein along its axis, the notches running normal to the axis aroundthe circumference of the roller. Into these several notches are forcedresilient O-rings such as O-ring 34. These O-rings maintain a tightnon-slippage bond with the roller 30 and a low pressure contact with theupper idler roller 36 of the last set of pinch rollers. The idler rolleris driven in a clockwise rotation, as viewed in FIG. 1, when the lowerroller 30 is driven. The idler roller 36 rests on the O-rings positionedon the roller 30 by the force of gravity due to its own weight. Itsshaft 38 is journaled through the super structure 9 in such a mannerthat a body of the roller 26 may maintain its touching contact with theO-rings 34.

A notch 40 in approximately the midpoint along the axis of the lowerroller 30, formed generally in the same manner and to the samedimensions as the notches supporting the O-rings, is cut into the lowerroller 30. The upper idler roller 36 is formed of a metal cylinder. Theroller 36 is divided approximately at its linear midpoint and turned orotherwise formed to permit a groove thereat. The shafts 32 and 38 arepositioned within the super structure 8 such that the center notch inthe drive roller 30 and the grooved portion in the roller 36approximately coincide.

A buckler finger 42 is fastened to the super structure 8 by hinge 44such that the finger 42 may rotate in a vertical direction. The fingeris further positioned to lie between rollers 30 and 36 in the area ofthe groove on roller 36. The finger is generally arcuate in shape andextends from its hinge point, above and behind (relative to the path oftravel of a sheet) the axis of rollers 30 and 36 extending through theportion therebetween, where notch 40 and the division of roller 36coincide, to a point in front of the rollers and below the path thatwould be traveled by a sheet guided through the trans port system.

At the hinge portion 44, there is a protrusion 46 appended to the finger42 and extending rearward therefrom within the super structure 8 (seeFIG. 1). Contacting the protrusion 46 is an adjustable spring arm 48capable of exerting an upward force on the protrusion 46 (see FIG. 1)which in turn operates on finger 42 as a lever system the pivot point ofwhich is at hinge 44. The force exerted causes the finger 42 to bebiased downward toward roller 30 and below the tangent line which may bedrawn through the contact points of the rollers 30 and 36 which wouldrepresent the path of a sheet traveling therethrough. The spring arm 48is adjustable by moving clamp 50 relative to the spring arm pivot point52 where the spring arm 48 is attached to the super structure 8. Bymoving the adjustment clamp 50 toward the pivot point 52 of the springarm 48, and therefore, away from the hinge 44 and the protrusion 46, thetension exerted by spring arm 48 on the protrusion 46 is reduced,thereby causing a lesser downward bias on the finger 42. Likewise, amovement of clamp 50 toward the hinge 44 will cause a greater downwardforce on the finger 42.

As a sheet, for example sheet 54, is transported through the superstructure 8 by the pinch rollers and guide plates positioned therein, itis brought to, and carried through, the rollers 30 and 36 until its leadedge contacts the lower arcuate surface of the finger 42. As the rollerscontinue to drive the sheet forward, the lead edge in contact with thefinger 42 is depressed or buckled therebeneath and so remains throughoutthe drive thereunder. The passage of the sheet under the finger 42causes an upward force on said finger and it is moved vertically upwardto some extent, depending upon the bias put thereon, by spring 46 andspring arm 48. This bias may be adjusted by the adjusting clamp 50 sothat the sheet 54 is depressed downward at its contact point with finger42 to impart a sufficient force on the sheet to maintain it in a rigidstate while it is expelled from the transport super structure 8. Theforce must not be so much as to crease the sheet along its line ofcontact with finger 52.

The beam strength required by a sheet of paper to prevent if frombuckling may be discovered from the following formula:

E T IV Stlffness 5 X E where:

tensile stress tensile strain E =Youngs modulus force/area change oflength/ original length force original length area X change of lengthand a severe anti-stiffness effect as the same is increased; therefore,making it more diflicult to prevent buckling as more of a sheet passesthe pinch rollers 34 and 36. However, an exponential increase instiffness may be imparted to the sheet by increasing the effectivethickness T by inducing a deflection across the cross-section as isaccomplished by this apparatus.

In order to achieve the desired deflection to increase T with differentstocks of sheet material fed through the transport, it is necessary toadjust the force exerted by the finger 42 on the sheet 54. It is forthis reason that an embodiment such as that shown in FIG. 1 isbeneficial in that the biasing force downward of the finger 42 isadjustable through spring 48. However, in some situations, such as maybe found in copying machine apparatus, the variation in thickness orweight of stock being transported would not be great enough tonecessitate a fully adjustable system. For this reason an antibuckleapparatus such as that embodied in FIG. 3 would be sufficient to achievethe desired results. Here the finger 42 is again pivotally fastenedabove the path of travel of a sheet which would be coincidental with atangent line drawn between roller 56 and O-ring 58, the latter beingmounted on roller 60.

A downward bias is achieved on finger 42 by means of a protrusion 62attached thereto and extending on the same side of an imaginary verticalline passed through pivot point 64 around which the finger 42 mayvertically rotate. The protrusion 62 may be of a heavier material thanthe finger 42 or it may be formed of the same material but weighted insuch a manner that it creates a moment arm in relation to the pivotpoint 64 forming a lever with point 64 as its fulcrum and exerting adownward force on the finger 42, such force directly related to itsweight and the distance thereof from the fulcrum point. By pre-selectingthe materials to be transported past a deflection finger one maydetermine the weight of the protrusion 62 which would most effectivelyoperate in conjunction with the finger 42 to prevent buckling of theselected sheet material.

The surface of finger 42 which is contacted by the transported sheetshould be a smooth, low friction surface formed not only to deflect thesheet as required for achieving the desired anti-buckle results but alsoto guide the sheet and prevent its catching on the finger and moving outof its predetermined path of rising along the lower surface toward thehinge for example.

The copy tray is back leaning in relation to the transport system. Thatis to say it is tilted from the horizontal rearward wtih its forwardportion being at a point vertically higher than its most rear portion.The tilt is generally at 15 from the horizontal although this is not alimitation nor limiting feature. It is designed to have an angle withthe horizontal approximately equal to the angle of the last flange 66 ofthe guide means 24 of the transport apparatus. Because the sheet emergesin a rigid state, due to the effect on it by the deflector finger 42, itmaintains the same angle with the horizontal as the guide plate segment66. Since this corresponds with the angle of the copy tray 10 to thehorizontal, the sheet is presented parallel to the bottom of the copyholder tray and when released by the transport apparatus will fall flatonto the copy tray or the preceding sheet gathered thereon.

FIG. 2 manifests a more simplified version of the deflector fingerembodied in a transport apparatus super structure 8. The guide means andpinch rollers may be the same as those shown in FIG. 1 including the setof final pinch rollers 36 and 30. Here, however, the deflector finger 68is rigidly fastened to the super structure 8 at the top front portionthereof in a position in front of the final set of pinch rollers. Thefinger is positioned to interfere with the path of travel of the sheetbeing transported through the super structure and does not ride up as asheet passes therebeneath, but is precisely positioned to maintain theexact deflection necessary to achieve the desired result of rigidity ofthe sheet passing thereunder by imparting to the sheet the requisitebeam strength.

The amount of intereference between the bottom por-- tion of finger 68and the path of travel of a sheet transported through the superstructure is predetermined and pre-set by moving the fastening screw 70,and with it the finger 68, forward and back in relation to the pinchrollers 30 and 36 along an elongated slot 72 in the super structure 8.Once adjusted, the finger will so remain until a further externaladjustment is made. If, however, the apparatus is used for a singlestock of sheet material it would not be necessary to provide easilyaccessible adjustment means since a single setting will be all that isnecessary to impart the proper deflection in the sheet to cause it to berigid but not to crease under the force exerted by the deflectionfinger.

While the invention has been described with reference to the structuredisclosed herein, it is not confined to the details set forth; and thisapplication is intended to cover such modifications or changes as maycome within the purposes of the improvements or scope of the followingclaims.

What is claimed is:

1. A sheet handling apparatus for preventing sheets from buckling whilebeing transported in a partially unsupported condition comprising atransport means of a predetermined width adapted to move a sheet along apredetermined path of travel,

a resilient member interposed in the path of travel of the sheet andpositioned between the edges of the transport means to urge the sheetout of and below the path of travel at the contact point causing thesheet to be depressed with the portion of the sheet contacting saidmember moved to a plane below the remainder of the sheet, and

means to maintain said member in a position that extends through thepath of travel as a sheet is transported past the member so that thesheet contacts said member and is depressed at the area of contacttherebetween, said member increasing the beam strength of the sheetsufliciently to prevent the buckling thereof,

said member being shaped and positioned to prevent the marring of thesheet by forming a crease therein.

2. The apparatus of claim 1, wherein said member is an elongated fingerhaving a biasing means associated therewith to maintain said member in aposition wherein it extends into the path of travel of a sheet.

3. The apparatus of claim 1, said transport means having associatedtherewith a sheet receptacle, said receptacle tilting rearward towardsaid transport from the horizontal.

4. The apparatus of claim 1, wherein said transport means includes atleast one pair of pinch rollers and said member is positioned in thepath of travel developed by said pinch rollers such that it contacts asheet traveling along the path of travel.

5. The apparatus of claim 1 wherein said means to maintain said memberin a position that extends substantially into the path of travelincludes means to pivotally mount said member to resiliently extend intothe path of travel of a sheet whereby it is urged away from the paththough maintained therein as a sheet passes into operable contacttherewith.

6. The apparatus of claim 1 wherein said member has 5 associatedtherewith means to fasten said member above the path of travel of asheet, said member extending through the path of travel and adapted tomove slightly toward said means to fasten said member as a sheet passesbeneath said member, contacting the surface thereof.

7. The apparatus of claim 1 wherein said means to maintain said memberin a position that extends substantially into the path of travelincludes means to mount said member to extend into the predeterminedpath of travel, said means to mount adapted to move said member to aposition being relatively greater removed from the predetermined path oftravel as a sheet passes into operable contact with said member.

8. The apparatus of claim 1, wherein said member is positionedapproximately midway across the width of said transport means.

9. A sheet handling apparatus for preventing sheets from buckling whilebeing transported in a partially unsupported condition comprising atransport means of predetermined width adapted to move a sheet along apredetermined path of travel,

an elongated finger having a biasing means associated therewith tomaintain the finger in a position wherein it extends into the path oftravel of the sheet and is positioned between the edges of saidtransport means to urge the sheet out of the path of travel at thecontact point, spring in biasing contact with said elongated fingeradapted to exert a force thereon in a direction opposite to that exertedby a sheet being moved in contact therewith, said force being capable ofovercoming the force exerted on the finger by a sheet, whereby saidmember depresses the sheet in the area of contact sufliciently toprevent the buckling thereof.

10. The apparatus of claim 9, wherein said spring is a cantilever barand has further associated therewith a movable fulcrum for varying itseflective length and, therefore, the force it exerts on said member.

11. The apparatus of claim 9, wherein said means to maintain said memberin a position that extends substantially into the path of travelincludes a weighted arm intimately attached to said member, 50 saidweighted arm arranged to exert a force on said member in the samedirection as the force of gravity exerts on said weighted arm wherebysaid weighted arm acts as a lever in relation to said member.

References Cited UNITED STATES PATENTS 3,224,705 12/1965 Nash 226-883,095,192 6/1963 Simjiam 271--71 3,291,485 12/1966 Darwin 271-71 RICHARDE. AEGERTER, Primary Examiner.

